生活百科：耳鸣与耳朵的保护系列之四——耳朵的结构

　　Here we have the outer ear and here's the ear canal. This yellow is fat. This blue is cartilage and this is the outer ear canal. Here is the eardrum. Behind the eardrum is the middle ear and behind the middle ear is the inner ear.

　　The outer ear in an adult is two-thirds bone and one-third cartilage which is blue. In a child it's reversed. At birth the outer ear canal is two-thirds cartilage and only one-third bone.

　　And this is where your wax is made. Sound waves come in and the eardrum vibrates. And there are three little bones of hearing that take the sound energy that is impacting upon the eardrum and present it to the inner ear. And what we can see in this model, this is what your eardrum looks like and on the inside are the little bones of hearing.

　　The inner ear has two parts. The organ of hearing which is curled up like a snail called the cochlea and the organ of balance which is called the labyrinth or the semicircular canals.

　　The middle ear space contains air and the air gets in through a tube called the Eustachian tube.

　　The Eustachian tube connects the back of your nose with your middle ear and the Eustachian tube allows air into your ear. Designed by God or Darwin depending upon which one you prefer.